Radio systems (e.g., wireless devices) are affected by a variety of factors, including the communication standards, frequencies, powers and waveforms of signals of the wireless devices, as well as signals of other wireless devices in the vicinity. Further, the number of different types of radios, such as IEEE 802.11 (WiFi), IEEE 802.16 (WiMAX), Bluetooth, Global System for Mobile Communication (GSM), High Speed Packet Access (HSPA), Long-Term Evolution (LTE) and the like, integrated into a single wireless device is generally increasing, resulting in co-existence problems. Therefore, in order to design communication devices, it is desirable to emulate radio scenes that accurately simulate such factors in a real world operating environment, in order to test viability of proposed schemes, as wells as robustness of waveforms against interferers.
Further, future cognitive radio systems may have to make use not only of databases, but also of radio frequency (RF) sensing engines to identify holes in the spectrum for signal transmission. To properly test such sensing engines, stimulus signals should mimic radio scenes that may be encountered, generally over a wide frequency band.
However, conventional radio scene emulators are static in nature and quite limited in scope and capability. For example, one conventional solution for testing LTE signals enables the user to combine LTE signals with only W-CDMA waveforms, which is not sufficient for in-depth testing.
In order to increase data rates, future to-be-deployed standards, such as LTE-Advanced, will introduce the so-called carrier aggregation feature, which stands for transmission of information over several (non) frequency adjacent carriers. The possibility of transmitting information using different types of waveforms (e.g., LTE and CDMA) over different bands is also being investigated. To properly test such future standards, complete radio scenes must be emulated, thus going beyond capabilities of conventional single-carrier, single-waveform devices.